1. Field of the Invention
The invention relates to an image processing apparatus for, particularly, dividing an input image into a character area, an area of a figure, a table, or the like in an electronic apparatus such as an OCR (optical character recognizing) apparatus, copying apparatus, facsimile apparatus, or the like.
2. Related Background Art
In a conventional image processing apparatus, there is an apparatus using a run length analyzing method as area dividing means whereby a distribution of run lengths is examined and a character area, a figure area, or the like is divided in accordance with a length of a white run or a black run. Another apparatus uses a spectrum analyzing method whereby a Fourier spectrum of an input image is analyzed and the input image is divided into various kinds of areas. Yet another apparatus uses a projection analyzing method whereby projections (histograms) in the vertical and horizontal directions are alternately repeatedly obtained and the area is divided from the information of a peripheral portion as disclosed in JP-A-1-15889.
The above conventional techniques, however, have problems such that it takes an extremely long time for arithmetic operating processes. Further, processes are executed to the pixels of an image, so that a memory area increases significantly, and a dividing precision of a complicated area construction to the image is low.
In the conventional image processing apparatus, as an area dividing means, there a method is used whereby a discrimination regarding whether an area is a table or another area is made on the basis of a ratio of the area of a circumscribed rectangle and the number of pixels, and the area is divided on the basis of the result of the discrimination.
The above conventional technique, however, has a problem such as in the case where a separator or the like (modified separator) formed by complicated polygonal lines is handled as one area. When the number of pixels for the area of the circumscribed rectangle increases, such an area is erroneously recognized as a table area and a dividing precision of the area decreases.
In the conventional image processing apparatus, in the case where the attributes (character, figure, table, etc.) of the divided area is erroneously discriminated, the area data which was erroneously discriminated is eliminated and a correct area frame is newly designated by a manual operation of the operator.
In a conventional technique such that the correction of the divided area is executed by a manual operation of the operator, in the case where a plurality of erroneous divided areas exist, there is a problem such that a burden on the operator increases and a long time is needed as a ratio to the processing time of the whole image processes.
In such a type of well-known image processing apparatuses, in the case where the image area was erroneously divided, area data of the erroneous area is eliminated and the operator newly designates the correct area frame by frame using a pointing device or the like.
The above conventional technique, however, has problems such that in case of a complicated area construction, a burden of the operation of the operator increases, it takes an extremely long time as a ratio to the processing time of the whole image processes.
In consideration of the above problems, it is an object of the invention to provide an image processing apparatus which can realize the reduction of the processing time when an area is divided, the decrease in size of a recording area and the improvement of a dividing precision of a complicated area construction. After an input image is thinned out, it is further converted into rectangle data by using a labeling and an area is divided into a character area and an area of a figure or photograph, a table, a separator, an index, or the like. Therefore, there are effects such that without changing the existing electronic parts and circuits, (1) reduction in processing time, (2) decrease in size of a memory area, (3) improvement of a dividing precision of a complicated area construction are obtained.
According to the invention, the input image is converted into rectangle data and is classified into a character area and an area of a figure, photograph, table or separator and, further, partial histograms of the left and right edges in the vertical and horizontal directions of the area which was temporarily determined to be a table area are calculated and compared, thereby deciding whether the area is a table area or not. There are, consequently, effects such that without changing the existing electronic parts and circuits, or the like, (1) an improvement of the precision is obtained for the division of a complicated area construction, particularly, the division of an area construction including a table, and (2) the processing time is short because the histograms are partially obtained.
According to the invention, an input image is converted into rectangle data and is classified into a character area and an area of a figure or a photograph, table or separator, and further the rules in the vertical and horizontal directions of the area which was temporarily decided as a table area are detected and counted, thereby deciding whether the area is a table area or not. Thus, there is an effect such that without changing the existing electronic parts or circuits (1) the improvement of the precision is obtained for the division of a complicated area construction, particularly, the division of an area construction including a table.
According to the invention, an input image is converted into rectangle data and is classified into a character area or an area of a figure or a photograph, table or separator and a ratio of the area in a frame to the area of the area which was temporarily decided as a table area is obtained. When such a ratio is equal to or larger than a threshold value, the area is determined to be a table. Thus, there are effects such that without changing the existing electronic parts or circuits,
(1) an improvement of the precision is obtained for the division of a complicated area construction, particularly, the division of an area construction including a table,
(2) since the area in the frame is used, even when the table frame slightly lacks, the decision about the table can be accurately performed,
(3) since the area in the frame is used, the decision about the table is strong for an inclination and can be accurately performed.
According to the invention, by combining the erroneously divided areas and correcting the erroneously presumed attributes, there are effects such that without changing the existing area dividing process, (1) an operating efficiency can be improved and (2) a processing time can be reduced.
It is another object of the invention to provide an image processing apparatus which can combine erroneously divided areas by a simple operation and the attributes of each area can be also easily corrected.
By providing correcting means for integratedly combining special divided areas, the erroneously divided areas are combined and, further, the necessary area attributes can be corrected. Therefore, without changing the existing area dividing process, (1) an operating efficiency can be improved and (2) a processing time can be reduced.